首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   5312篇
  免费   464篇
  国内免费   9篇
耳鼻咽喉   33篇
儿科学   102篇
妇产科学   141篇
基础医学   973篇
口腔科学   105篇
临床医学   530篇
内科学   971篇
皮肤病学   184篇
神经病学   790篇
特种医学   206篇
外科学   517篇
综合类   44篇
一般理论   4篇
预防医学   371篇
眼科学   138篇
药学   274篇
中国医学   8篇
肿瘤学   394篇
  2024年   15篇
  2023年   97篇
  2022年   135篇
  2021年   242篇
  2020年   169篇
  2019年   219篇
  2018年   247篇
  2017年   195篇
  2016年   251篇
  2015年   252篇
  2014年   285篇
  2013年   319篇
  2012年   510篇
  2011年   489篇
  2010年   243篇
  2009年   220篇
  2008年   324篇
  2007年   266篇
  2006年   267篇
  2005年   250篇
  2004年   175篇
  2003年   187篇
  2002年   153篇
  2001年   26篇
  2000年   21篇
  1999年   19篇
  1998年   27篇
  1997年   26篇
  1996年   18篇
  1995年   12篇
  1994年   14篇
  1993年   5篇
  1992年   10篇
  1991年   8篇
  1990年   7篇
  1989年   3篇
  1988年   7篇
  1987年   5篇
  1986年   6篇
  1985年   3篇
  1983年   4篇
  1981年   5篇
  1979年   4篇
  1972年   3篇
  1964年   2篇
  1962年   2篇
  1961年   2篇
  1933年   4篇
  1931年   2篇
  1926年   5篇
排序方式: 共有5785条查询结果,搜索用时 31 毫秒
91.
92.
The present study aimed to elucidate the profile of coping in patients with obsessive–compulsive disorder (OCD) in order to discern whether the disorder is characterized by an excess of maladaptive coping skills and/or a lack of adaptive coping skills. Sixty individuals with OCD were compared with 110 individuals with depression and 1050 nonclinical controls on the Maladaptive and Adaptive Coping Styles Questionnaire (MAX). Psychopathology was assessed with the Obsessive–Compulsive Inventory-Revised (OCI-R), the Yale-Brown Obsessive–Compulsive Scale (Y-BOCS), and the Patient Health Questionnaire-9 for depression (PHQ-9). Individuals with OCD and depression displayed more maladaptive coping and avoidance as well as less adaptive coping than nonclinical controls. Importantly, adaptive coping was significantly lower in individuals with OCD than in those with depression at a medium effect size, whereas the clinical groups were indistinguishable on maladaptive coping and avoidance. Lack of adaptive coping was strongly correlated with resistance to symptoms and poor insight in OCD (Y-BOCS), even after controlling for depression. Lack of adaptive coping skills may represent a specific pathogenetic factor in OCD. Longitudinal studies need to clarify whether strengthening adaptive skills during childhood and adolescence may help to prevent the progression from subclinical to manifest OCD.  相似文献   
93.

Objective

To identify predictors for employment status after 10 years in a cohort of people with multiple sclerosis (MS), with the aim to increase knowledge concerning factors present at an early stage that are important for working life and work-life balance.

Design

A 10-year longitudinal observational cohort study.

Setting

University hospital.

Participants

A consecutive sample of people with MS (N=154) of working age were included at baseline, of which a total of 116 people participated in the 10-year follow-up; 27 people declined participation and 11 were deceased.

Interventions

Not applicable.

Main Outcome Measures

Baseline data on personal factors and functioning were used as independent variables. Employment status 10 years after baseline, categorized as full-time work, part-time work, and no work, was used as the dependent variable. A generalized ordinal logistic regression was used to analyze the predictive value of the independent variables.

Results

Predictors for full- or part-time work after 10 years were young age (P=.002), low perceived physical impact of MS (P=.02), fatigue (P=.03), full-time work (P=.001), and high frequency of social/lifestyle activities (P=.001) at baseline. Low perceived physical impact of MS (P=.02) at baseline also predicted full-time work after 10 years.

Conclusions

This study underlines the complexity of working life for people with MS, and indicates that it may be valuable to give more attention to the balance between working and private life, both in clinical practice and future research, to achieve a sustainable working life over time.  相似文献   
94.
95.
Altered mesolimbic dopamine signaling has been widely implicated in addictive behavior. For the most part, this work has focused on dopamine within the striatum, but there is emerging evidence for a role of the auto-inhibitory, somatodendritic dopamine D2 receptor (D2R) in the ventral tegmental area (VTA) in addiction. Thus, decreased midbrain D2R expression has been implicated in addiction in humans. Moreover, knockout of the gene encoding the D2R receptor (Drd2) in dopamine neurons has been shown to enhance the locomotor response to cocaine in mice. Therefore, we here tested the hypothesis that decreasing D2R expression in the VTA of adult rats, using shRNA knockdown, promotes addiction-like behavior in rats responding for cocaine or palatable food. Rats with decreased VTA D2R expression showed markedly increased motivation for both sucrose and cocaine under a progressive ratio schedule of reinforcement, but the acquisition or maintenance of cocaine self-administration were not affected. They also displayed enhanced cocaine-induced locomotor activity, but no change in basal locomotion. This robust increase in incentive motivation was behaviorally specific, as we did not observe any differences in fixed ratio responding, extinction responding, reinstatement or conditioned suppression of cocaine, and sucrose seeking. We conclude that VTA D2R knockdown results in increased incentive motivation, but does not directly promote other aspects of addiction-like behavior.  相似文献   
96.
97.
98.
We are presenting a case of floating left and right atrial formations on an atrial septal defect occluder system (23mm StarFLEX)-Occluder) initially supposed to be thrombotic appositions in a 57-year-old man. The closure was performed on the background of left hemispheric stroke and atrial septal aneurysm (ASA) with patent foramen ovale (PFO). The suspect structures were detected in the 6-month follow-up by transesophageal echocardiography (TEE). The patient underwent a successful surgical explantation of the closure device and closure of the patent foramen ovale (PFO) using a pericardial patch. The pathological evaluation of the biatrial device associated appositions revealed hytrophic heart muscle tissue with perifocal scarring and purulent abscess-forming, granulating and foam-cell including inflammatory foreign body reaction instead of the expected thrombus formation.  相似文献   
99.
The double-stranded RNA (dsRNA)-dependent protein kinase (PKR) is induced as part of the IFN response in mammals and acts to shut down protein synthesis by the phosphorylation of eukaryotic initiation factor 2alpha (eIF2alpha). In fish, a PKR-like kinase activity has been detected, but the enzyme responsible has eluded characterization. Here, we describe a PKR-like kinase from zebrafish. Phylogenetic analysis shows that the C-terminal kinase domain is more closely related to the kinase domain of PKR than to any of the other three known eIF2alpha kinases. Surprisingly, instead of the two dsRNA binding domains found at the N terminus of PKR, there are two Zalpha domains. Zalpha domains specifically bind dsDNA and RNA in the left-handed Z conformation, often with high affinity. They have been found previously in two other IFN-inducible proteins, the dsRNA editing enzyme, ADAR1, and Z-DNA binding protein 1 (ZBP1), as well as in the poxvirus virulence factor, E3L. This previously undescribed kinase, designated PKZ (protein kinase containing Z-DNA binding domains), is transcribed constitutively at low levels and is highly induced after injection of poly(inosinic)-poly(cytidylic) acid, which simulates viral infection. Binding of Z-DNA by the Zalpha domain of PKZ was demonstrated by circular dichroism. PKZ inhibits translation in transfected cells; site-directed mutagenesis indicates that this inhibition depends on its catalytic activity. Identification of a gene combining Zalpha domains with a PKR-like kinase domain strengthens the hypothesis that the ability to bind left-handed nucleic acid plays a role in the host response to viruses.  相似文献   
100.
Background/Aims: The aim of the study was to assess the impact factor of HCV and HGV in fulminant hepatic failure.Methods: The 5′-untranslated regions of HCV RNA and HGV RNA and a segment of the core antigen sequence of HBV were amplified after extracting the nucleic acids from snap-frozen tissue aliquots from explanted livers of 26 consecutive patients undergoing orthotopic liver transplantation for fulminant hepatic failure preoperatively diagnosed as either autoimmune (n=2), HAV/HBV (n=8), toxic (n=4) or aetiologically unknown (n=12).Results: HCV RNA was detected in five of 26 (19.2%) livers with fulminant hepatic failure. All five HCV RNA-positive livers belonged to the group of non-toxic, non-autoimmune liver failure (n=20), three of them were found in the group of liver failure with unknown aetiology (n=12) and two in the group of HBV-associated liver failure (n=7), making an HCV incidence of 25%, 25%, and 28.6%, in the different groups, respectively. HGV RNA was detected in 10 of 17 (58.8%) explants and in all four groups of fulminant hepatic failure as defined preoperatively. HBV DNA was identified in six livers of 26 patients (23.1%) with fulminant hepatic failure. Neither HCV RNA nor HBV DNA was detected in the livers of patients with toxic or autoimmune fulminant hepatic failure.Conclusions: These results indicate that HBV and HCV, but not HGV, play an aetiologic role in fulminant hepatic failure. HCV-positive cases were concentrated either in the group of otherwise unexplained fulminant hepatic failure or in the group of HBV fulminant hepatic failure. HGV-positive cases, on the other hand, were found within all four preoperatively defined groups, indicating a role as cofactor rather than as single aetiologic agent.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号